package com.demo.websocket;

import com.demo.heartbeat.MyServerHandler;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.stream.ChunkedWriteHandler;
import io.netty.handler.timeout.IdleStateHandler;

import java.util.concurrent.TimeUnit;

/**
 * @author gy
 * @date 2022/6/12
 */
public class MyServer {
    public static void main(String[] args) throws Exception{
        // 创建两个线程组
        NioEventLoopGroup bossGroup = new NioEventLoopGroup(1);
        NioEventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();

            serverBootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();

                            // 因为基于http协议，使用http的编码和解码器
                            pipeline.addLast(new HttpServerCodec());
                            // 是以块方式写，添加 ChunkedWriteHandler 处理器
                            pipeline.addLast(new ChunkedWriteHandler());
                            /**
                             * 说明：
                             * 1. http数据在传输过程中是分段，HttpObjectAggregator 起的作用，
                             *  就是可以将多个段聚合
                             * 2. 这就是为什么，当浏览器发送大量数据时，就会发出多次http请求
                             */
                            pipeline.addLast(new HttpObjectAggregator(8192));
                            /**
                             * 说明：
                             * 1. 对应 websocket，它的数据以 帧（frame）形式传递
                             * 2. 可以看到 WebSocketFrame 下面有六个子类
                             * 3. 浏览器请求时 ws://localhost:7000/hello
                             * 4. WebSocketServerProtocolHandler 核心功能是将 http协议升级为 ws协议，保持长连接
                             * 5. 是通过 状态码 101 来切换的
                             */
                            pipeline.addLast(new WebSocketServerProtocolHandler("/hello"));

                            // 自定义的 handler，处理业务逻辑
                            pipeline.addLast(new MyTextWebSocketFrameHandler());

                        }
                    });
            // 启动服务器
            ChannelFuture channelFuture = serverBootstrap.bind(7000).sync();
            channelFuture.channel().closeFuture().sync();

        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}
